The presence of a high molecular weight angiotensinogen (H-Aogn) has been documented in human plasma. H-Aogn levels are increased in high estrogen states. H-Aogn is significantly elevated in women with pregnancy induced hypertension as compared to normotensive pregnant women. Thus it is proposed to document the level of H-Aogn in other states in which total angiotensinogen is increased. This includes high glucocorticoid states, uremic states, and states with high angiotensin levels. Human low molecular weight angiotensinogen (L-Aogn) has been purified. It is proposed to characterize the reaction between purified human renin and human angiotensinogen by means of kinetic studies. The inhibitory effect or lack thereof of human alpha 2-antiprotease, human alpha 2-macroglobulin, and human des-angiotensin I-angiotensinogen on this reaction will be documented.